In the semiconductor processing industry, various individual components are combined in order to form an integrated device. For example, in flip-chip or wire-bond semiconductor processing, two or more components may be bonded to one another for purposes of electrical interconnection, heat dissipation, ease of manufacturing, or the like. For example, a conventional electronic device 10 is illustrated in FIG. 1A, wherein the device (e.g., a “ball grid array” package) may be electrically coupled to one or more other electronic components (not shown). The device 10, for example, comprises a plurality of solder balls (not shown) associated with the substrate, wherein the solder balls generally provide an electrical connection between the device and the other electronic component(s).
In a typical device 10, a die 12 is coupled to a substrate 14, wherein the die and substrate are physically bonded to one another, as well as electrically connected to one another. The die 12, for example, comprises an integrated circuit 15, wherein a plurality of electrically conductive leads 16 extend therefrom, and wherein the plurality of leads are operable to electrically connect the die to the substrate 14. In conventional processing, prior to electrically connecting the die 12 to the substrate 14, the die and substrate are physically bonded to one another via an adhesive 18 that has been applied to one or more of the die and the substrate. Conventionally, the adhesive 18 comprises a fluid-like epoxy that is operable to be cured by an application of heat thereto (e.g., a “baking” process), thus generally bonding the die 12 to the substrate 14.
Once the die 12 and substrate 14 are physically bonded to one another, the plurality of leads 16 associated with the die may be electrically connected to a plurality of bonding pads 20 associated with the substrate, thus electrically coupling the die to the substrate. For example, after the adhesive 18 is cured, each of the plurality of leads 16 is soldered to a respective bonding pad 20, wherein the plurality of leads are further operable to electrically connect the die 12 to the one or more other electronic components (not shown) associated with the device 10. In conventional processing, however, the connection of the leads 16 to the bonding pads 20 can be deleteriously affected if one or more constituents of the adhesive 18 bleeds onto one or more of the bonding pads 18. For example, in conventional processing, the adhesive 18 comprises a fluid-like resin 22 that will tend to bleed onto a surrounding region 24 of the surface 26 of the substrate 14 prior to the curing of the adhesive (e.g., during the time that elapses between the application of the adhesive and the baking process).
As illustrated in FIG. 1A, and further in the partial cross-section of FIG. 1B, such a bleeding of the resin 22 has a potential to contaminate one or more of the bonding pads 20, thus deleteriously affecting the bonding of the leads 16 thereto. For example, conventional bonding pads 20 are generally associated with the surface 26 of the substrate 14, wherein the bonding pads have been generally exposed in previous processing performed on the substrate, such as via an etching process performed on the surface of the substrate. Accordingly, a top surface 28 of each of the bonding pads 20 is generally associated with the surface 26 of the substrate 14. Consequently, the resin 22, upon bleeding into the surrounding region 24 of the surface 26 of the substrate 14, can easily bleed onto the top surface 28 of one or more of the bonding pads 20, such as by capillary action. Once the resin 22 has bled onto the top surface 28 of one or more of the bonding pads 20, capillary forces associated with the top surface of the bonding pads will have a tendency to pull even greater amounts of resin onto the bonding pads. Therefore, upon reaching the surrounding region 24, the resin 22 has a great potential to contaminate the top surface 28 of the bonding pads 20, wherein the contamination can deleteriously affect the electrical connection of the leads 16 thereto. For example, “non-stick” issues can arise, wherein the resin 22 residing on the top surface 28 of the bonding pad 20 generally causes a poor solder connection 30 between the lead 16 and the bonding pad, thus leading to a potential failure of the device 10.
Conventionally, undesirable affects from the bleed of resin 22 are minimized by providing a large bleed area 32 on the substrate 14 for the resin to bleed onto, thus locating the bonding pads 20 at a relatively large distance from the die 12. However, as real estate on substrates becomes more and more valuable due to ever decreasing sizes of associated electronic devices, providing such a large bleed area 32 becomes less practical. Accordingly, a need exists in the art for an economical device for preventing resin bleed onto bonding pads, such that a size of the device can be minimized, and wherein reliable electrical connections can be made between the respective leads and bonding pads.